Miniaturized flat spool relay

ABSTRACT

The invention relates to a microrelay comprising a magnetic spool, a contact support body ( 2 ) within which contacts are arranged, a permanent magnet ( 32 ) and an armature ( 31 ) which is tiltable around it&#39;s axis between two positions, as well as a spring-loaded reversing system. The inventive micro relay is characterized in that the magnetic spool system ( 1 ) is configured as a flat spool system ( 1 ) in the form of a microstructure arranged on a flow plate ( 11 ) and is composed of at least one flat microspool ( 12 ′). The pivoting armature ( 31 ′) can itself be configured in the form of a three pole magnet ( 32 ′) or a two pole magnet ( 32 ″). The inventive microrelay has a minimal overall height and can be produced in a cost effective way in an automated manufacturing process.

The present invention concerns a micro-relay consisting of a magneticcoil system, a contact carrier body with contacts arranged therein, apermanent magnet for the magnetic yoke and a rotor which can be tiltedabout its central axis between two positions and a switching springsystem.

A multiplicity of relays with wound coils are known. EP, A1 0 373 109for example discloses circuit board relays where a wound coil by way ofa permanent magnet causes, by way of an induced magnetic flux, a rotorto perform a tilt movement whereby switching contact springs areactivated. The disadvantage here, however, remains the lower limit ofthe resulting construction height due in particular to the spacerequired for the wound coil, which restricts the applicability of suchrelays. Also the relatively high manufacturing costs of the wound coiland the complexity have proven disadvantageous.

The task of the invention is to provide a micro-relay of the typedescribed initially which has a minimum construction height, containsonly a few components and can be produced at low cost in automatedproduction.

According to the invention this task is solved in that the magnetic coilsystem is formed as a flat coil system in the form of a microstructureproduced on a flux plate and comprises at least one micro-flat coil.Advantageous and further developed embodiments of the object of theinvention are the subject of the dependent claims.

The flat coil system preferably has two individually arranged micro-flatcoils.

The invention is described in more detail using the design examplesshown in the drawing which are also the subject of dependent claims.These show:

FIG. 1 an exploded view of the individual parts of the relay;

FIG. 2 an interior view of the long side of the main element of therelay with the contact carrier body removed;

FIG. 3 an embodiment similar to that of FIG. 2;

FIG. 4 an embodiment similar to that of FIG. 3;

FIG. 5 an embodiment similar to that of FIG. 2;

FIG. 6 an embodiment similar to that of FIG. 5;

FIG. 7 an embodiment similar to that of FIG. 6;

FIG. 8 an embodiment of the drive of the micro-relay with a centrallyarranged flat coil, and

FIG. 9 the transfer of the tilt movement of the rotor to the switchingsprings.

The multiple embodiments of the object of the invention—as shown inFIGS. 1 to 8—cannot be achieved in the same easy way with otherpreviously known processes.

FIG. 1 shows the individual assemblies of the micro-relay in explodedview, namely a flat coil system 1, a contact carrier body 2 and a rotorand switching spring holder 3.

The flat coil system 1 consists of a flux plate 11 and two micro-flatcoils 12 and 13 applied to this which are produced in a known mannerusing a suitable etching process from the specialist area ofmicrostructure technology and powered by way of connecting tabs 26, 26′.The flat coil system 1, designed as a microstructure, serves as a drivefor the tilt movement of the rotor 31 to activate the switching springs33 and 34.

The contact carrier body 2 is a frame-like plastic injection mouldingholding six terminal lugs by the surrounding injection moulding. The twolong sides of contact carrier body 2 hold terminal lugs 27, 28, 29 and27′, 28′, 29′ respectively for the switching contacts.

In the rotor and switching spring holder 3 is arranged a rotor 31designed as a prismatic rod which at the same time can be formed as apermanent magnet 32. Connections 35 and 36 are welded to points 40 and41. As FIG. 9 shows, as a result of its tilt movement the rotor 31activates the switching springs 33 and 34 which in turn close workingcontacts 37, 37′ and rest contacts 38, 38′ into the correspondingposition.

FIG. 2 shows an inner view of the long side of the relay according tothe invention where the corresponding side walls of the contact carrierbody are cut away. The magnetic flux _(E1) induced by the excitedmicro-flat coil 12 acts against the magnetic flux _(M1) caused by thepermanent magnet 32′. The magnetic flux _(E2) induced by the excitedmicro-flat coil 13 however supports the magnetic flux _(M2) caused bythe permanent magnet 32′ whereby the attraction force of the partmagnets on the side of the air gap 14 becomes greater than the retainingforce of the part magnets on the other side so that the permanent magnet32′ formed as rotor 31′ tilts over its edge 18 or its curved contour 18′into the working position. The movement is transferred to the switchingsprings 33, 34 in the known manner whereby the switching process of themicro-relay is triggered. In order to return the permanent magnet to theother position, the resulting fluxes must be set such that the tiltmovement is triggered with the help of the supporting spring effect ofthe switching springs 33, 34. This can be achieved by switching thepolarity of the power source.

FIG. 3 shows an embodiment in which permanent magnet 32 induces in rotor31 the magnetic fluxes _(M1) and _(M2) with different flux direction.The magnetic flux _(E) induced by micro-flat coils 12 and 13 by way ofcores 15 and 16 in the permanent magnet 32 supports magnetic flux _(M2)and acts against magnetic flux _(M1) so that the rotor 31 tilts into theworking position. In order to return the rotor to the other position theflux direction of the micro-coil flux I_(E) must be reversed, forexample in the same way as described in the section above.

The functional method of the embodiment in FIG. 4 is similar to that ofthe previous section where the cores 15′ and 16′, arranged in the centreof the micro-flat coils 12 and 13, have a height which is only slightlyabove the thickness of the micro-coils.

FIG. 5 shows an embodiment where in contrast to FIG. 2 the rotor 31′ isdesigned as a two-pole permanent magnet 32″. The magnetically conductivecentral core 17 causes an amplification of magnetic flux _(E1). Themagnetic flux _(M) is around twice as great as the magnetic flux _(E1).Therefore flux _(M) is shown as a double line. _(E1) is subtracted from_(M), _(E2) is added to _(M), whereby in a similar manner to thatdescribed above, the tilt movement of the rotor 31′, designed as apermanent magnet, is triggered.

FIG. 6 shows an embodiment based on FIG. 5 with a magneticallynon-conductive rotary support 17′ instead of a magnetically conductivecentral core. Because of the greater resistance due to the air gap, asmaller magnetic flux _(E1) results. The ratio _(E1) to _(E2) is lessthan in the embodiment described under FIG. 5 as there is a greaterresistance over the air gap with the rotary support. The functionalprinciple remains the same.

FIG. 7 shows an embodiment according to FIG. 6 with the difference thatthe rotary axis 18′″is further away from the flux plate 11. The mounting19 of rotary axis 18′″can be provided on the contact carrier body 2.

FIG. 8 shows an embodiment with a single micro-flat coil 12′ arrangedabout a magnetically conductive central core 17. The magnetic fluxes_(E1) and _(M) are subtracted and magnetic fluxes _(E2) and _(M) added,whereby again a tilt movement is achieved of the rotor 31′, designed asa permanent magnet 32″ in the manner already described.

The function of the micro-relay is now briefly described with referenceto FIG. 1.

The flat coil system, designed as a microstructure, serves to drive thetilt movement of rotor 31. The tilt movement is triggered by thecorresponding interaction of magnetic fluxes _(E1), _(M1), _(E2), _(M2),_(E), _(M) as explained in detail above. Because of its tilt movement,the rotor activates the switching springs 33 and 34 which in turn closeworking contacts 37, 37′ and rest contacts 38, 38′ respectively into thecorresponding position.

The advantages of the object of the invention are that low constructionheights can be achieved. It is essential that the flat coil systemproduced according to the invention allows a miniaturisation of therelay. By layer construction the coils of the contacts can be separatedin an optimum manner. Also due to the use of modern galvanic processesproduction of the flat micro-coils is particularly favourable in themanner known to the expert. A reduction in conductor insulation achievesa very high efficiency. In contrast to conventional wound coils, itallows a massive reduction in process steps for production. Thus forexample soldering of the coil ends and the associated use of flux agentswhich can be contact-damaging for the microclimate of the relay, can beomitted. Also low-cost joining technologies e.g. bonding can be used.The insulation material of conventional insulation of the coil wiresalso has a negative effect on the microclimate. A further advantage ofthe present invention is consequently the omission of thiscontact-damaging insulation material. The use of a flux plate made ofiron as a system carrier ensures an extraordinarily stable preconditionfor SMD suitability. There is therefore a high temperature stability forthe SMD solder process.

What is claimed is:
 1. Micro-relay consisting of a magnetic coil system,a carrier body with contacts arranged therein, a rotor operating as apermanent magnet and as a return path for the induced magnetic flux ofat least one coil, the rotor is tiltable about a central axis betweentwo positions to activate a switching spring system, where the magneticcoil system is formed as a flat coil system in the form of amicrostructure produced on a flux plate and comprises at least onemicro-flat coil, wherein the rotor is swivellable about the centralaxis, and is formed as one of (1) a 3-pole permanent magnet and (2) a2-pole permanent magnet.
 2. Micro-relay according to claim 1 includingtwo micro-flat coils and between the two micro-flat coils is arranged amagnetically conductive central core also formed flat.
 3. Micro-relayaccording to claim 1 wherein the rotary axis of rotors lies at a defineddistance above the flux plate.